package com.fingard.dsp.bank.directbank.cmb02.util;

//Cipher - an encryption template
//
//Copyright (C) 1996 by Jef Poskanzer <jef@mail.acme.com>.  All rights reserved.
//
//Redistribution and use in source and binary forms, with or without
//modification, are permitted provided that the following conditions
//are met:
//1. Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
//
//THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
//ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
//IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
//ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
//FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
//DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
//OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
//HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
//LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
//OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
//SUCH DAMAGE.
//
//Visit the ACME Labs Java page for up-to-date versions of this and other
//fine Java utilities: http://www.acme.com/java/

/// An encryption template.
//<P>
//<A HREF="/resources/classes/Acme/Crypto/Cipher.java">Fetch the software.</A><BR>
//<A HREF="/resources/classes/Acme.tar.gz">Fetch the entire Acme package.</A>
//<P>
//@see StreamCipher
//@see BlockCipher
//@see EncryptedOutputStream
//@see EncryptedInputStream

public abstract class Cipher extends CryptoUtils {

	// / Constructor.
	public Cipher(int keySize) {
		this.keySize = keySize;
	}

	// / How big a key is. Keyless ciphers use 0. Variable-length-key
	// ciphers
	// also use 0.
	public int keySize;

	// / Return how big a key is.
	public int keySize() {
		return keySize;
	}

	// / Set the key from a block of bytes.
	public abstract void setKey(byte[] key);

	// Utility routines.

	// / Utility routine to set the key from a string.
	public void setKey(String keyStr) {
		setKey(makeKey(keyStr));
	}

	// / Utility routine to turn a string into a key of the right length.
	public byte[] makeKey(String keyStr) {
		byte[] key;
		if (keySize == 0)
			key = new byte[keyStr.length()];
		else
			key = new byte[keySize];
		int i, j;

		for (j = 0; j < key.length; ++j)
			key[j] = 0;

		for (i = 0, j = 0; i < keyStr.length(); ++i, j = (j + 1) % key.length)
			key[j] ^= (byte) keyStr.charAt(i);

		return key;
	}

}
